The median sternotomy is a very usual operation in the field of heart surgery.
The sternum or its portion of a patient is sawn by a saw or other cutting means. When all the sternum is severed in two, its sternal halves are spread apart laterally the one from the other so that mediastinum structures can be exposed. As a result, a large aperture is formed in the thoracic cavity, which permits an optimal surgical access to the heart and great vessels and also is well tolerated by the patient.
Once the operation is completed, the two sternal halves are rejoined. Traditionally, several means, such as Mersilene fibres, steel wires, metal and plastic bands, nitinol clamps, etc. are used for a sternal closure in order to assure the sternal stability and the recovery of the patient. The most usual current method of doing this is to use steel wires around the sternum passing through intercostal spaces.
However, both the medial sternotomy and the current methods are not free of complications. The complications of the sternal wound, usually due to the sternum instability, range from prolonged thoracic pains, which cause inconveniences and related respiratory disorders up to the dehiscence of the wound at the risk of infections and mediastinitis.
U.S. Pat. No. 4,583,541 already provides a sternal stabilizer for holding a severed sternum closed. Such a stabilizer consists essentially of a single strap-like member, which is adapted to overlie, in longitudinal and centrally relation, the anterior surface of a divided sternum of a patient. Such a strap-like member is provided with a plurality of pairs of through holes. A plurality of wires extend from the sternum posterior surface through holes formed in the sternum concentrically to the strap-like member through holes and are tied or twisted together within a central groove.
The above patent would intend to overcome problems occurring with the complications seen after median sternotomies. These problems range from wires breaking, wires protruding through the skin e.g. upon a patient's slimming, separation of the sternal halves, failure of the sternum to heal, infections and loose or unstable sternal halves.
Differently from the above patent that intends to protect a sternal stabilizer which appears to be limited in its function due to the need of fitting together holes in the sternum and those in the strap-like member, this invention aims to create a partial or full reinforcement for one sternal half or both, considering that sternotomy operations are carried out more often in elderly patients, whose skeletal system is losing more and more its strength in time.
Therefore, an object of the present invention is to provide a device adapt to be used in the sternal closure that provides a lateral reinforcement to the sternal halves as well as to both anterior and posterior portions of the sternum.
Another object of the invention is to perform a sternal closure similar to that could be made through a wire binding, without any risk of rubbing of the wire on the sternum which could generate subsequent lesions and consequent partial or complete fractures and wire loosening.
A further object of the invention is to permit a closure also in parts affected by partial or complete fractures of the sternum, which are subsequent to a primary operation.
Yet a further object of the invention is to allow the sternal halves be closed during an operation for sternal dehiscence particularly without being necessary to separate any adherence being formed in meanwhile, which would involve a high risk of damage to the heart and any bypasses and relevant ducts.
Yet another object of the invention is to reinforce sternums which can be closed again by traditional methods at the risk of complications, owing to ageing or degeneration processes, such as the osteoporosis process, on patients that are affected also by diabetes, respiratory insufficiency, or obesity, or that have been subjected to paramedian sternotomies.